Metal Stress Factors On Ultrasound Propagation Mode

Working status of metallic materials subjected to the stress affected materials,measuring the stress distribution of metallic materials not only provide the basis formaterial evaluation, but also to predict metal fatigue strength conditions, control metalcutting process, the inspection process to eliminate the effect of stress, etc. Currently stresstesting technology is mainly divided into two categories, non-destructive testing techniquesand lossy detection technology. Destructive testing techniques are generally interested inthe workpiece is detected with a certain degree of damage, the impact parameters of theworkpiece, the workpiece will not work detecting damage detection NDT. NDT ultrasonicdetection method is the most commonly used detection method, in which the steel sufferedthe most effective method of tangential stress detection using critically refracted wavedetection method to detect. Critically refracted longitudinal waves is a special ultrasoniclongitudinal wave, it has the basic characteristics of ultrasonic longitudinal wavepropagates along the surface while the work its spread can usually reach a depth of severalwavelengths. Steel material tangential stress detection to ensure the safe operation ofindustrial engineering to improve the reliability of great significance.In order to study the steel subjected to different tensile/compressive stress, thecritically refracted wave velocity relations trends and plate type and the size of the stressbetween. The use of third-order elastic constants ultrasonic measurement method tocalculate the relationship between stress and velocity, and by Snell’s law of refractionstudied the mechanism of the critical wave. When using ANSYS finite element simulationsoftware, applying different stress on the steel plate cutting, critically refracted wavepropagation velocity were hidden in the steel sheet the explicit simulation to solve.Experimental platform to determine the critical waveform detected the presence ofrefracted waves, as well as on the plate were affected4MPa,6MPa, when the tension/compression stress8MPa, using critically refracted wave detection principle stress plateassay to determine the plate subjected to tension/compression stress to the step increaseswhen2MPa, critically refracted wave velocity change trends and changes in volume. Concluded that the critical velocity of propagation of refracted waves in the steelsheet as the steel sheet subjected to the stress increases, on the contrary, the tensile stressincreases with the velocity decreases third order elastic constants analyzed by ultrasonicmeasurement methods. Finite element simulation analysis using ANSYS criticallyrefracted wave velocity changes in steel by different stresses. Experimental verification ofthe existence of the critical refraction, and the steel sheet subjected to the stress of2MPawhen the step increases, the critical velocity of refracted waves in7.32m/s increase, asopposed to tensile stress in the steel sheet by steps of2MPa length increases, the criticalrefracted wave velocity dropped to8.78m/s.